Commitments - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 2016	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Long-term Purchase Commitment [Line Items]
Satellite performance incentives obligation, Noncurrent		$ 25,324,000	$ 18,181,000
Description of operating lease arrangements		The Company leases office and other facilities under non-cancelable operating leases which expire between fiscal year 2020 and fiscal year 2033 with initial terms ranging from one to 15 years and which provide for pre-negotiated fixed rental rates during the terms of the lease. Certain of the Company’s facilities leases contain option provisions which allow for extension of the lease terms.
Rent expense		$ 53,500,000	$ 41,200,000	$ 34,000,000.0
Minimum [Member]
Long-term Purchase Commitment [Line Items]
Non-cancelable operating leases initial term		1 year
Maximum [Member]
Long-term Purchase Commitment [Line Items]
Non-cancelable operating leases initial term		15 years
Satellite Capacity Agreements [Member]
Long-term Purchase Commitment [Line Items]
Future minimum payments on purchase commitments for fiscal year 2020		$ 68,400,000
Future minimum payments on purchase commitments for fiscal year 2021		53,000,000.0
Future minimum payments on purchase commitments for fiscal year 2022		25,600,000
Future minimum payments on purchase commitments for fiscal year 2023		19,800,000
Future minimum payments on purchase commitments for fiscal year 2024		1,800,000
Future minimum payments on purchase commitments thereafter		0
ViaSat-1 and ViaSat-2 Satellites [Member]
Long-term Purchase Commitment [Line Items]
Satellite performance incentives obligation		28,200,000
Satellite performance incentives obligation, current		2,900,000
Satellite performance incentives obligation, Noncurrent		25,300,000
ViaSat-1 and ViaSat-2 Satellites [Member] | Satellite Performance Incentives Obligation [Member]
Long-term Purchase Commitment [Line Items]
Commitment amount		37,000,000.0
Future minimum payments under satellite performance incentives obligation for fiscal year 2020		2,600,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2021		2,800,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2022		3,300,000
Future minimum payments under satellite performance incentives obligation for fiscal year 2023		5,000,000.0
Future minimum payments under satellite performance incentives obligation for fiscal year 2024		5,300,000
Future minimum payments under satellite performance incentives obligation thereafter		$ 18,000,000.0
ViaSat-3 Class Satellites [Member] | Capital Addition [Member]
Long-term Purchase Commitment [Line Items]
Commitment amount	$ 390,100,000